# Octagon (EntityTopic, 12)

(Difference between revisions)
 Revision as of 22:05, 16 February 2014 (view source)Hayate (Talk | contribs) (polytope explorer integration)← Older edit Latest revision as of 16:05, 26 March 2017 (view source) Line 3: Line 3: | name=Octagon | name=Octagon | dim=2 | dim=2 - | elements=8, 8 + | elements=8 [[digon]]s, 8 [[point]]s | genus=0 | genus=0 | ssc=G8 | ssc=G8 Line 11: Line 11: | extra={{STS Matrix| | extra={{STS Matrix| 8 0 8 0 - 1 1}}{{STS Uniform polytope + 1 1}}{{STS Polytope + | dual=''self-dual'' + | bowers=Oc}}{{STS Uniform polytope | wythoff=3 | 2 3 or | 2 2 2 | wythoff=3 | 2 3 or | 2 2 2 - | schlaefli={8} + | schlaefli={8}, t{4} - | vfigure=[[Digon]], length 1 + | dynkin=x8o, x4x - | dual=''Self-dual'' + | vfigure=[[Digon]], length √(2+√2) }}}} }}}} + An octagon is a polygon with 8 sides. It is the truncated [[square]]. + ==Coordinates== + The coordinates of a regular octagon with side two are all permutations of: +
(±1, ±(1+√2))
== Equations == == Equations == *The area of a regular octagon with side length ''l'' is: *The area of a regular octagon with side length ''l'' is:

## Latest revision as of 16:05, 26 March 2017

An octagon is a polygon with 8 sides. It is the truncated square.

## Coordinates

The coordinates of a regular octagon with side two are all permutations of:

(±1, ±(1+√2))

## Equations

• The area of a regular octagon with side length l is:
2(1 + √2) · l2

## Dissection

The octagon of side 1 may be dissected into 8× isosceles triangle with sides {1,2×√(1+√22)}.

## Incidence matrix

Dual: Self-dual

 # TXID Type Name Va Ea 0 Va = point ; 1 Ea 2 = digon ; 2 8a 8 8 = octagon ;

## Usage as facets

 Notable Dishapes Flat: triangle • square • pentagon • hexagon • octagon • decagon Curved: circle

## Pages in this category (1)

 Octagonal prism